always directive managed for add_header option

templates/etc/nginx/sites-available/_base.j2

@@ -62,7 +62,7 @@ server {
 
 	# --> Custom headers
 {% for key, value in __headers.iteritems() %}
-	add_header {{ key }} {{ value }};
+	add_header {{ key }} {{ value | replace(' always', '') }}{% if nginx_version.stdout | version_compare('1.7.5', 'ge') and ' always' in value %} always{% endif %};
 {% endfor %}
 	# <-- Custom headers